1. Field of the Invention
The present invention relates to tissue expansion devices, in particular, it relates to a substantially flat skin expander that is substantially flat when in a non-expanded state and to methods of making such a skin expander.
2. Description of the Prior Art.
Expansion of skin and subcutaneous tissue by implantation of expandable devices have received great acceptance. Such devices develop an expanded layer of skin that is to be used on a recipient area of a patient. Such devices have also been used to expand breasts to develop a cavity to receive a breast prosthesis. Skin expanders have also been used in reconstructive breast surgery, expanding the reconstructed site so that a breast prosthesis can be implanted.
As in all surgical procedures, it is desirable to make the expander implant procedure as least obtrusive to the patient as possible. In implanting a skin expander, an incision is made through the skin and the subcutaneous tissue. The skin expander is then placed between the subcutaneous tissue and muscle or bone, depending on the area of the body in which the skin expander is implanted. It is desirable to make the incision as small as possible so that the implantation of the skin expander is as inobtrusive as possible to the patient.
The Radovan et al U.S. Pat. No. 4,217,889 and the Austad U.S. Pat. No. 4,157,085 illustrate conventional skin expanders. Such skin expanders have a base and an expansion cover attached to the base. The expansion cover is spaced from the base even when the skin expander is in a non-expanded state. To insert such a skin expander beneath the subcutaneous tissue, an unnecessarily large incision must be made in order to insert the skin expander Alternatively, the skin expander could be folded and inserted through a smaller incision. However, upon expansion, the skin expander may not unfold in the manner desired causing problems during expansion
One type of mammary prosthesis also includes an expandable chamber. Examples of such prostheses are disclosed in the following patents:
______________________________________ Inventor Patent No. ______________________________________ Bejarano 4,263,682 Mohl et al 3,663,968 Koneke et al 3,852,833 Pangman 2,842,775 Lake 4,095,295 Bartolo 4,428,364 Cox, Jr. 4,178,643 Lynch 3,883,902 Arion 3,860,969 Boone 3,600,718 ______________________________________
All of the breast prostheses described in the above-mentioned patents require a larger than necessary incision since the breast prostheses, in their expanded state, include an expansion chamber prior to being filled with a fluid.